scholarly journals New Sources of Adult Plant and Seedling Resistance to Puccinia coronata f. sp. avenae Identified among Avena sativa Accessions From the National Small Grains Collection

Plant Disease ◽  
2018 ◽  
Vol 102 (11) ◽  
pp. 2180-2186 ◽  
Author(s):  
Belayneh Admassu-Yimer ◽  
Tyler Gordon ◽  
Stephen Harrison ◽  
Shahryar Kianian ◽  
Harold Bockelman ◽  
...  
Keyword(s):  
Avena Sativa ◽  
Agricultural Research ◽  
Field Tests ◽  
The United States ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Adult Plant ◽  
United States Department ◽  
Seedling Resistance ◽  
Small Grains

Accessions of cultivated oat (Avena sativa L.) from the United States Department of Agriculture–Agricultural Research Service Small Grains Collection in Aberdeen, ID were characterized for adult plant resistance (APR) and seedling resistance to crown rust, caused by Puccinia coronata f. sp. avenae. Initially, 607 oat accessions with diverse geographic origins were evaluated in field tests in Baton Rouge, LA. Of those, 97 accessions were not fully susceptible and were tested in the field in St. Paul, MN against a diverse P. coronata f. sp. avenae population. Thirty-six accessions that had some level of resistance in both field tests and mean coefficients of infection of ≤20 were further evaluated for APR and seedling resistance. Among these, four accessions (PI 193040, PI 194201, PI 237090, and PI 247930) were resistant to eight P. coronata f. sp. avenae races as seedlings. Twenty-nine accessions had resistance to at least one of the P. coronata f. sp. avenae races. Three accessions (CIav 2272, CIav 3390, and PI 285583) were fully susceptible to all eight P. coronata f. sp. avenae races as seedlings. Further evaluation of the three seedling-susceptible accessions at the flag leaf stage in a growth chamber resulted in moderately susceptible to moderately resistant responses. The resistance sources presented here may contain genes not deployed in elite oat varieties, and may be useful for future crown rust resistance breeding. The adult and seedling resistance found in accessions of the cultivated oat species is especially valuable because it avoids problems associated with the transfer of genes from wild species to cultivated oat.

scholarly journals Characteristics of Resistance to Puccinia coronata f. sp. avenae in Avena fatua

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2616-2624 ◽  
Author(s):  
Edyta Paczos-Grzeda ◽  
Sylwia Sowa ◽  
Aneta Koroluk ◽  
Tim Langdon
Keyword(s):  
Resistance Genes ◽  
Rust Resistance ◽  
The United States ◽  
Avena Fatua ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
United States Department ◽  
Seedling Resistance ◽  
Infection Pattern ◽  
Crown Rust Resistance

Crown rust, caused by Puccinia coronata f. sp. avenae, is the most widespread and harmful fungal disease of oat. The best defense against the pathogen is use of cultivars with genetic resistance, which is effective, economic, and an environmentally friendly alternative to chemical control. However, the continuous evolution of the pathogen can rapidly overcome major gene resistance, creating an urgent need to identify new sources. Wild oat accessions have already proven to be valuable donors of many resistance genes, but the weed species Avena fatua remains underexploited. Its abundance across multiple environments and the frequent occurrence of herbicide-resistant populations demonstrate its ready ability to adapt to biotic and abiotic stresses; yet, surprisingly, there are no extensive studies which describe crown rust resistance occurrence in gene bank stocks of A. fatua. In this study, 204 accessions of A. fatua maintained in the collections of the United States Department of Agriculture (USDA) and Polish National Centre for Plant Genetic Resources were evaluated at the seedling stage for crown rust reaction using host–pathogen tests with five highly diverse and virulent races of P. coronata. Of tested genotypes, 85% showed a heterogeneous infection pattern, while 61% were susceptible or moderately susceptible to all races. Of the 79 resistant A. fatua accessions, seedling resistance to at least two P. coronata isolates was recognized within 19 accessions, with 13 displaying a homogeneously resistant phenotype to one or two races. Accessions showing multiple single seedling resistance to three or four isolates were observed. Based on the seedling reaction to isolates used in the study, 18 infection profiles (IP) were determined. Using UPGMA clustering, resistant accessions were divided into six main clusters encompassing samples with similar IPs. Twelve of 18 patterns allowed us to postulate the likely presence of novel crown rust resistance genes, whose origin was predominantly from Kenya or Egypt. Future work will clarify the genetic basis of the resistances observed here, as well as confirm their potential utility in breeding resistant oat cultivars.

scholarly journals Sources and Genetics of Spot Blotch Resistance to a New Pathotype of Cochliobolus sativus in the USDA National Small Grains Collection

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 1988-1993 ◽  
Author(s):  
Yueqiang Leng ◽  
Rui Wang ◽  
Shaukat Ali ◽  
Mingxia Zhao ◽  
Shaobin Zhong
Keyword(s):  
United States ◽  
Dominant Gene ◽  
The United States ◽  
Spot Blotch ◽  
Cochliobolus Sativus ◽  
Adult Plant ◽  
United States Department ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Small Grains

Spot blotch, caused by Cochliobolus sativus, is one of the important barley diseases in the northern Great Plains of the United States and the Prairie Provinces of Canada. The disease has been under control for almost five decades due to the use of durable spot blotch resistance derived from the barley line ND B112. However, the emergence of isolate ND4008 with virulence on ND B112 prompted us to identify new sources of resistance to this new pathotype. In this study, we screened 2,062 barley accessions from the United States Department of Agriculture National Small Grains Collection for spot blotch resistance, and identified 40 barley accessions exhibiting a high level of resistance to isolate ND4008 at the seedling stage. In all, 24 of the barley accessions with seedling resistance also exhibited moderate to high adult plant resistance to ND4008 in greenhouse tests. Seven of the ND4008-resistant barley accessions showed seedling resistance to two other pathotypes (1 and 2) of the pathogen. Genetic study of resistant barley accessions PI 235186, PI 592275, and PI 643242 indicated that a single major dominant gene controls spot blotch resistance to ND4008 in each of these three accessions. These resistant sources are useful for developing barley cultivars with spot blotch resistance to all pathotypes of C. sativus.

scholarly journals Additional Sources of Broad-Spectrum Resistance to Puccinia coronata f. sp. avenae from Canadian Accessions of Avena barbata

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1405-1410 ◽  
Author(s):  
M. L. Carson
Keyword(s):  
United States ◽  
Broad Spectrum ◽  
Rust Resistance ◽  
The United States ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Adult Plant ◽  
United States Department ◽  
Ploidy Levels ◽  
Broad Spectrum Resistance

Crown rust (Puccinia coronata f. sp. avenae) is considered the most damaging disease of oat and the use of race-specific seedling (Pc) genes for resistance has been the primary means of control. As these resistance genes from cultivated oat, Avena sativa, and the wild hexaploid animated oat, A. sterilis, were deployed in oat cultivars, corresponding virulence in the U.S. crown rust population increased rapidly, such that the effective lifespan of a resistant cultivar in the United States is now 5 years or less. Introgression of resistance from diploid and tetraploid Avena spp. into hexaploid oat has been difficult due to the difference in ploidy levels and the lack of pairing of homeologous chromosomes between species. The wild tetraploid slender oat, A. barbata, has been a source of powdery mildew and stem rust resistance in cultivated oat but has largely been unexploited for crown rust resistance. A relatively high percentage of A. barbata accessions from the United States Department of Agriculture (USDA) National Small Grains Collection were resistant to a highly diverse crown rust population in recent tests. Tests of 1,099 A. barbata accessions from the Canadian Plant Gene Resources Center not represented in the USDA collection revealed that a similar percentage (11.4%) were at least moderately resistant at the seedling and adult plant stage when tested with a highly diverse bulk inoculum derived from the St. Paul buckthorn nursery. Eighteen accessions were rated as highly resistant or a mix of highly resistant and resistant plants in both seedling and adult plant tests. Three accessions (CN21531 from Italy and CN26271 and CN26305 from Spain) displayed a unique “blotchy” resistant reaction as adult plants. Resistant accessions were found from throughout much of the natural range of A. barbata but the Western Mediterranean and Lebanon had the highest frequency of accessions with broad-spectrum resistance.

scholarly journals Virulence of Oat Crown Rust in Brazil and Uruguay

Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 802-808 ◽  
Author(s):  
K. J. Leonard ◽  
J. A. Martinelli
Keyword(s):  
Avena Sativa ◽  
Western Siberia ◽  
Specific Resistance ◽  
The United States ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
South American ◽  
Oat Crown Rust ◽  
High Virulence ◽  
Important Disease

Race-specific resistance to crown rust, the most important disease of oat (Avena sativa) in Bra-zil, often fails within a few years of use in Brazilian cultivars. Virulence of 144 isolates of Puccinia coronata from cultivated oat in Brazil in 1997 to 1999 and 36 isolates from Uruguay in 1994-95 and 1998 was tested on a set of 27 oat crown rust differentials lines, each with a different Pc gene for race-specific resistance. Frequencies of virulence and mean virulence complexity were compared among these five collections from Brazil and Uruguay as well as with mean virulence complexity for a collection of 17 isolates from cultivated oat in western Siberia in Russia. Virulence-avirulence for each of the 27 Pc genes was polymorphic in both Brazil and Uruguay. Virulence frequencies were similar for collections from Brazil in 1998 and 1999 and for the collection from Uruguay from 1998, but there were large differences between the 1997 collection and the 1998 and 1999 collections from Brazil. Mean virulence complexity in both Brazil and Uruguay was greater than reported in the United States and much greater than in the Russian collection of P. coronata. A large number of races of P. coronata were found, with no more than five isolates of any race found in a single year in Brazil or Uruguay. The high virulence complexity and great diversity of virulence polymorphisms in Brazil and Uruguay make it unlikely that race-specific resistance can be effective there even though the South American populations of P. coronata are apparently entirely asexual.

Inheritance of resistance to Puccinia coronata avenae and P. graminis avenae in an accession of Avena sterilis from Spain

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 198-202 ◽  
Author(s):  
D. E. Harder ◽  
J. Chong ◽  
P. D. Brown ◽  
J. W. Martens
Keyword(s):  
Stem Rust ◽  
Dominant Gene ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Adult Plant ◽  
Single Dominant Gene ◽  
Avena Sterilis ◽  
Seedling Resistance ◽  
Puccinia Coronata Avenae ◽  
Plant Stage

Accessions of wild Avena spp. obtained from the Iberian Peninsula were screened for resistance to oat crown and oat stem rust. Of a number of accessions which showed resistance, A. sterilis accession IB3056 was selected for further genetic analysis because it had combined resistance to both crown and stem rusts and as a hexaploid was readily hybridizable with A. sativa. IB3056 was crossed and backcrossed with the susceptible cultivar 'Makuru' and progeny were analyzed for segregation to a range of rust races. A single dominant gene conferred resistance to crown rust. The resistance was highly effective against all isolates of Puccinia coronata avenae tested. The crown rust resistance of IB3056 was due either to gene Pc68 or was very closely linked or allelic to Pc68. Seedling plants of the IB3056 parent were susceptible to all isolates of P. graminis avenae tested, but in the adult plant stage they were resistant. All IB3056/2* Makuru progeny also were susceptible to stem rust as seedlings, but BC1F2 adult plants segregated for resistance in ratios indicating a single dominant gene, designated Pg17.Key words: oat crown rust, oat stem rust, adult plant resistance, seedling resistance

scholarly journals Screening Wild Oat Accessions from Morocco for Resistance to Puccinia coronata

Plant Disease ◽  
2013 ◽  
Vol 97 (12) ◽  
pp. 1544-1548 ◽  
Author(s):  
M. Y. A. Tan ◽  
M. L. Carson
Keyword(s):  
The United States ◽  
Seedling Stage ◽  
Puccinia Coronata ◽  
Adult Plant ◽  
United States Department ◽  
Wild Oat ◽  
Rust Disease ◽  
Adult Plant Stage ◽  
Plant Stage ◽  
Moderately Resistant

Here, we report the screening of 332 new accessions of 11 different wild oat (Avena) species from the United States Department of Agriculture National Small Grains Collection in Aberdeen, ID, for resistance to crown rust disease, caused by Puccinia coronata f. sp. avenae. This collection originated from Morocco and includes Avena agadiriana, A. atlantica, A. barbata, A. damascena, A. eriantha, A. hirtula, A. longiglumis, A. magna, A. murphyi, A. sterilis, and A. wiestii. After screening this collection with a highly diverse population of P. coronata f. sp. avenae, 164 accessions (49%) were rated moderately resistant to resistant in the preliminary screen at the seedling stage and 181 accessions (55%) rated moderately resistant to highly resistant in the adult plant stage. Although none of the accessions showed a highly resistant response consistently in the seedling stage, 20 accessions did display a highly resistant response in the adult plant stage. Both seedling as well as adult plant resistance was found in 150 (45%) of the accessions. Virulence in P. coronata has been reported to all resistance genes currently being used in North American oat cultivars. The new resistance sources presented here are potentially new sources for future breeding. The resistance found in 52 accessions of A. magna and A. murphyi with the AACC genome is especially valuable because these should be relatively easy to transfer into hexaploid A. sativa.

scholarly journals Incidence and Distribution of Puccinia coronata and P. graminis on Turfgrass in the Midwestern United States

Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 955-963
Author(s):  
Brijesh B. Karakkat ◽  
Vonte L. Jackson ◽  
Paul L. Koch
Keyword(s):  
United States ◽  
Stem Rust ◽  
Kentucky Bluegrass ◽  
The United States ◽  
Primary Objective ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Midwestern United States ◽  
Fungal Populations ◽  
Relationship Of

Crown rust (caused by Puccinia coronata) and stem rust (caused by P. graminis) are two common and destructive diseases of turfgrass in the United States. Crown rust has been associated with perennial ryegrass and stem rust with Kentucky bluegrass when identified based solely on fungal morphology. However, recent studies using molecular identification methods have indicated the host–pathogen relationship of rusts on turf to be more complex. Our primary objective was to quickly and accurately identify P. coronata and P. graminis in symptomatic turfgrass leaves over 3 years on turfgrass samples from across the Midwestern United States. Between 2013 and 2015, 413 samples of symptomatic cool-season turfgrass from Wisconsin and surrounding states were screened using real-time polymerase chain reaction. Of these samples, 396 were Kentucky bluegrass and 17% of them contained P. coronata, 69% contained P. graminis, and 13% contained both P. coronata and P. graminis. In addition, both year and location effects were observed on the distribution of Puccinia spp. collected annually from two locations in southern Wisconsin. This research supports previous conclusions that have identified variability among P. graminis and P. coronata host relationships on turfgrass, and further demonstrates that rust fungal populations on Kentucky bluegrass may not be consistent between locations in the same year or over multiple years at the same location. The increasing evidence of variation in the turfgrass rust populations will likely affect future rust management and turfgrass breeding efforts.

Armillaria novae-zelandiae.

2021 ◽  
Author(s):  
Ian Hood
Keyword(s):  
Agricultural Research ◽  
Disease Risk ◽  
Nutrient Recycling ◽  
The United States ◽  
Laboratory Culture ◽  
Root Disease ◽  
White Rot ◽  
United States Department ◽  
Planted Forests ◽  
Global Database

Abstract Armillaria novae-zelandiae is a white rot wood decay fungus and root disease pathogen that occurs in a number of countries in the Southern Hemisphere and in parts of tropical and subtropical Asia. It is not known to have been introduced to these regions, where it is presumed to be indigenous. Its designation as "invasive" is based on its propensity to establish colonies and disease centres in disease-free areas by dispersal of basidiospores from "toadstool" fruit bodies that appear on wood during the winter months. As a wood decomposer fungus A. novae-zelandiae contributes beneficially to carbon and nutrient recycling. Like many other Armillaria species it is recognized by characteristic white mycelial fans or ribbons produced beneath host bark and by its bootlace-like rhizomorphs by which it spreads vegetatively from colonized buried woody material or stump root systems to infect living host plants.Armillaria novae-zelandiae was the cause of substantial disease losses in plantations of Pinus radiata and orchards of kiwifruit vines (Actinidia deliciosa) in New Zealand from the 1970s to the 1990s. Its importance has since declined with changes in patterns of crop management, although it remains widely distributed. Much research into its control was undertaken during this period. In eastern states in Australia, A. novae-zelandiae is a minor cause of root disease in natural and planted forests, where it is of lesser importance than Armillaria luteobubalina. Its impact in other regions is unknown, but it has not been associated with reports of significant disease. Risk of unintended international spread appears to be low to negligible but should not be discounted. If intercepted, isolates of A. novae-zelandiae may be identified by laboratory culture testing or more rapidly and precisely by molecular sequencing procedures. A. novae-zelandiae is listed in the EPPO Global Database and features in the United States Department of Agriculture Agricultural Research Service fungal databases. It is considered a risk organism in Hawai'i.

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